Mood and motor trajectories in Parkinson's disease: Multivariate latent growth curve modeling.

Abstract

Objective Apathy is a common feature of Parkinson's disease (PD) that can manifest independently of depression, but little is known about its natural progression in medically-managed patients. The present study sought to characterize and compare trajectories of apathy, depression, and motor symptoms in PD over 18 months. Method Data from a sample of 186 PD patients (mean disease duration of 8.2 years) followed by the University of Florida Movement Disorders Center were obtained from a clinical research database. Scores on the Unified Parkinson's Disease Rating Scale (motor portion), Apathy Scale, and Beck Depression Inventory at three time-points (baseline, 6 months, 18 months) were analyzed in a structural equation modeling framework. Results A multivariate growth model controlling for age, sex, education, and disease duration identified linear worsening of both apathy (slope estimate = 0.73; p <.001) and motor symptoms (slope estimate = 1.51; p <.001), and quadratic changes in depression (slope estimate = 1.18; p = .07). All symptoms were positively correlated. Higher education was associated with lower apathy, depression, and motor severity. Advanced age was associated with greater motor and apathy severity. Female sex and longer disease duration were associated with attenuated motor worsening. Antidepressant use was associated only with depression scores. Conclusions These longitudinal results support the differentiation of apathy and depression in PD. Like motor progression, apathy progression may be linked at least partially to dopaminergic neurodegeneration. Empirically-supported treatments for apathy in PD are needed.

Mood Differences Among Parkinson’s Disease Patients With Mild Cognitive Impairment

“…Indeed, past studies have shown that depression, unlike apathy, does not follow the same trajectory as motor symptoms in PD; suggesting that multiple neurotransmitters such as serotonin, or norepinephrine may be involved {25,26}. Future studies are needed to elucidate the mechanism of depression, independent of apathy, in PD and to clarify the contribution of depression to cognitive profiles.…”

Preliminary Evidence of Apathetic-Like Behavior in Aged Vesicular Monoamine Transporter 2 Deficient Mice

“…However, the progression of apathy in PD is rather linked to the progression of the typical motor-symptoms than with depression (Zahodne et al, 2012), probably indicating independent roots for both conditions in the context of PD. In this line, apathy might be associated with a hypodopaminergic state in the mesocorticolimbic pathway in PD (Czernecki et al, 2008; Pagonabarraga et al, 2015), although lesions and neuroimaging studies suggest the dysfunction of frontal-subcortical circuits, especially those linking the ventromedial prefrontal cortex to related regions in the basal ganglia, also to be relevant for the development of apathy (van Reekum et al, 2005; Levy and Czernecki, 2006; Chase, 2011; Santangelo et al, 2013; Robert et al, 2014).…”

Motivational engagement in Parkinson's disease: Preparation for motivated action

“…Apathy is defined as a primary deficit in motivation associated with reduced goal-directed behaviors (Marin, 1991) and is highly prevalent in frontal-subcortical diseases such as Parkinson’s. In addition, data suggest that apathy may be related to Parkinson’s disease pathology itself, as Zahodne et al (2012) found that apathy follows a similar trajectory as motor symptom progression in Parkinson’s. Stuss and Alexander (2000) suggested that apathy results from a variety of deficits in the central nervous system, including affective (flattening of emotional responsiveness), behavioral (reduced initiation of spontaneous behavior), and executive dysfunction (difficulty planning/executing), processes that are interrelated and frequent concomitants of Parkinson’s disease.…”